7,245 research outputs found

    Enhancing the Quality of Argumentation in School Science

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    The research reported in this paper focussed on the design of learning environments that support the teaching and learning of argumentation in a scientific context. The research took place over two years between 1999 and 2001 in junior high schools in the greater London area. The research was conducted in two phases. In the first developmental phase, working with a group of 12 science teachers, the main emphasis was to develop sets of materials and strategies to support argumentation in the classroom and to assess teachers‘ development with teaching argumentation. Data were collected by videoing and audio recording the teachers attempts to implement these lessons at the beginning and end of the year. During this phase, analytical tools for evaluating the quality of argumentation were developed based on Toulmin‘s argument pattern. Analysis of the data shows that there was significant development in the majority of teachers use of argumentation across the year. Results indicate that the pattern of use of argumentation is teacher specific, as is the nature of the change. In the second phase of the project, teachers taught the experimental groups a minimum of nine lessons which involved socioscientific or scientific argumentation. In addition, these teachers taught similar lessons to a control group at the beginning and end of the year. Here the emphasis lay on assessing the progression in student capabilities with argumentation. Hence data were collected from several lessons of two groups of students engaging in argumentation. Using a framework for evaluating the nature of the discourse and its quality, the findings show that there was an improvement in the quality of students‘ argumentation. In addition, the research offers methodological developments for work in this field

    The effect of a visual/motion display mismatch in a single axis compensatory tracking task

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    The frequency response of visual systems is typically unity from 0 to 20 rad/sec, while that of motion systems typically falls off in the vicinity of 6 rad/sec. The question arises as to what effect, if any, such a difference in servomechanism performance has on the simulation. Is pilot performance reduced by the conflict between displays? Would a more realistic simulation occur if the visual servomechanisms were degraded to match the motion servomechanisms? Does the pilot need and use the higher frequency information present in the visual display? The purpose of the experiment is to take a step forward toward answering these questions. Work already in the literature which bears on these questions is outlined. A description is then given of an experiment used to check for the effects of a difference in the performance of the visual and motion servomechanisms (the experiment uses a single-axis, compensatory, roll-tracking task). The results of the experiment are then presented and analyzed

    MUSTANG 3.3 Millimeter Continuum Observations of Class 0 Protostars

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    We present observations of six Class 0 protostars at 3.3 mm (90 GHz) using the 64-pixel MUSTANG bolometer camera on the 100-m Green Bank Telescope. The 3.3 mm photometry is analyzed along with shorter wavelength observations to derive spectral indices (S_nu ~ nu^alpha) of the measured emission. We utilize previously published dust continuum radiative transfer models to estimate the characteristic dust temperature within the central beam of our observations. We present constraints on the millimeter dust opacity index, beta, between 0.862 mm, 1.25 mm, and 3.3 mm. Beta_mm typically ranges from 1.0 to 2.4 for Class 0 sources. The relative contributions from disk emission and envelope emission are estimated at 3.3 mm. L483 is found to have negligible disk emission at 3.3 mm while L1527 is dominated by disk emission within the central beam. The beta_mm^disk <= 0.8 - 1.4 for L1527 indicates that grain growth is likely occurring in the disk. The photometry presented in this paper may be combined with future interferometric observations of Class 0 envelopes and disks.Comment: 19 pages, 3 figures, AJ accepted, in pres

    Doubly stochastic continuous-time hidden Markov approach for analyzing genome tiling arrays

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    Microarrays have been developed that tile the entire nonrepetitive genomes of many different organisms, allowing for the unbiased mapping of active transcription regions or protein binding sites across the entire genome. These tiling array experiments produce massive correlated data sets that have many experimental artifacts, presenting many challenges to researchers that require innovative analysis methods and efficient computational algorithms. This paper presents a doubly stochastic latent variable analysis method for transcript discovery and protein binding region localization using tiling array data. This model is unique in that it considers actual genomic distance between probes. Additionally, the model is designed to be robust to cross-hybridized and nonresponsive probes, which can often lead to false-positive results in microarray experiments. We apply our model to a transcript finding data set to illustrate the consistency of our method. Additionally, we apply our method to a spike-in experiment that can be used as a benchmark data set for researchers interested in developing and comparing future tiling array methods. The results indicate that our method is very powerful, accurate and can be used on a single sample and without control experiments, thus defraying some of the overhead cost of conducting experiments on tiling arrays.Comment: Published in at http://dx.doi.org/10.1214/09-AOAS248 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

    Kekuatan Tarik Komposit Poliester Berpenguat Partikel Kayu Jati, Merawan Dan Meranti Merah

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    Komposit poliester dengan bahan penguat dari serbuk kayu jati, merawan dan meranti merah dari limbah industri pengergajian kayu dibuat dengan metode hand lay-up. Komposit dibuat dengan volume fraksi serbuka kayu 4, 8 dan 16%. Pengujian tarik dilakukan untuk mengetahui kekuatan masing-masing komposit serbuk kayu, menunjukan bahwa kekuatan tarik komposit lebih tinggi dari kekuatan tarik polyester murni. Sementara kekuatan tarik komposit menurun seiring dengan naiknya prosentase serbuk kayu. Kekuatan tarik tertinggi didapat pada komposit serbuk kayu merawan diikuti oleh komposit serbuk jati dan serbuk kayu meranti merah. Tingginya kandungan uap air menyebabkan rendahnya kekuatan tarik dari komposit serbuk kayu

    Sifat-sifat Mekanik Komposit Serat TKKS-Poliester

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    Empty Fruit Bunch (EFB) fiber reinforced polyester composites were prepared using simple technique namely hand lay-up. Alkali treatments were used to enhance the hydrophobicity of the fiber. Lignin and cellulose content of EFB were analysed through chemical composition analysis. The mechanical properties are analyzed by conducting tensile and flexural tests. Macro observation shows fiber bridging on the fracture section. The SEM micrograph also shows a better surface roughness after alkali treatmen. The result shows that bending strength increases with the increases of fiber volume fraction. Tensile strength and elastic modulus of composite were higher than the pure polyester and increases with the increasing of fiber volume fraction although polyester shows low compatibility with the EFB fiber. The failure mechanism as a result of bending and tensile tests had shown a dominant fiber pull-out mechanism and less of fiber breaking mechanism. It suggests that the optimal strength of the composite can be further increases by enhancing the compactibility between fiber and matrix

    Local Global Connections via Asian American Studies

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    In this presentation Shirley S. Tang will highlight the specific contexts, curriculum structures and pedagogical practices developed by the UMass Boston’s Asian American Studies Program, particularly in relationship with local Asian American communities and their transnational networks in Asia. She will share reflections and analysis on connections between her teaching and research in Asian American communities as a bilingual/bicultural immigrant faculty in an urban, public university in Boston, Massachusetts and her ongoing projects on civic engagement and service learning in Boston’s Asian American communities as well as her most recent experience supervising U.S. students in their participation in the 4th Asia-Pacific Regional Conference on Service Learning and other international learning activities in Hong Kong and Guangzhou, China

    Keynote Address: Thorny Issues and Slippery Slopes: Perspectives on Judicial Independence

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    The Teaching of Procedure Across Common Law Systems

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    What difference does the teaching of procedure make to legal education, legal scholarship, the legal profession, and civil justice reform? This first of four articles on the teaching of procedure canvasses the landscape of current approaches to the teaching of procedure in four legal systems—the United States, Canada, Australia, and England and Wales—surveying the place of procedure in the law school curriculum and in professional training, the kinds of subjects that “procedure” encompasses, and the various ways in which procedure is learned. Little sustained reflection has been carried out as to the import and impact of this longstanding law school subject. Through a comparative approach, this series of articles explores what difference the approach a particular jurisdiction has chosen to adopt makes for legal education, legal scholarship, the practice of law and the profession, and to civil justice reform in our legal system. En quoi l’enseignement de la procĂ©dure civile modifi e-t-il les Ă©tudes juridiques, la recherche juridique, la profession d’avocat et la rĂ©forme de la justice civile? Ce premier de quatre articles sur l’enseignement de la procĂ©dure dresse le tableau de l’approche actuellement utilisĂ©e dans quatre systĂšmes juridiques – aux États-Unis, au Canada, en Australie, en Angleterre et au Pays de Galles – et se penche sur la place qu’occupe la procĂ©dure dans le programme des facultĂ©s de droit et dans la formation professionnelle, les matiĂšres qui constituent la « procĂ©dure » et les diverses façons d’apprendre la procĂ©dure. L’importance et l’incidence de cette matiĂšre traditionnelle des facultĂ©s de droit ont fait jusqu’ici l’objet de fort peu de rĂ©fl exion en profondeur. Par le biais d’une approche comparative, cette sĂ©rie d’articles examine en quoi l’approche adoptĂ©e dans ces pays modifi e chez nous les Ă©tudes et la recherche juridiques, la pratique du droit, la profession d’avocat et la rĂ©forme du systĂšme de justice civile
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